1. Field of the Invention
The present invention relates to a mounting structure of an open/close valve in a sealed body used for a cushioning material and the like and a device for manufacturing a sealed body with the open/close valve.
2. Description of the Background Art
There have been types of a sealed body with a cushioning effect by filling air therein, being used as a cushioning material and the like. For example, they are “Sealed bag for fluid” by Japanese Utility Model Application Laid Open No. H01-164142, and “Cushioning material sheet,” which is a product of an apparatus published under WO95/18008.
These bags are something like a sealed bag 101, as shown in FIG. 7, that includes an expansion part 102 expanding with air filled therein, and an open/close valve 103 communicating the inside of the expansion part 102 and the outside of the sealed bag 101. These are made of soft resin sheets and sectioned by a bonded portion 104 by way of heat-sealing or the like.
The open/close valve 103 forms a flat air passage 103a in a manner sandwiched by the opposite sheets. As shown in FIG. 7(A), when the sheets are separated, the air passage 103a is left opened so that air may flow therethrough. On the contrary, as shown in FIG. 7(B), when the sheets are fitted closely each other, the air passage 103a is closed and air will not flow therethrough.
Herein, as for fixing of said open/close valve 103 to the expansion part 102 in the above-described sealed bag 101, it is usually done only by the bonded part 104 to seal the expansion part 102 and the open/close valve 103. That is, only both sides of the air passage 103a in the open/close valve 103 are fixed to the expansion part 102, while an intermediate part of the valve 103 is not fixed to anywhere.
And, with the expansion part 102 not filled with air, as shown in FIG. 7(D), the sheets of the expansion part 102 and the ones of the open/close valve 103 are respectively laid one on top of another.
On contrary, with the expansion part 102 filled with air, the sheets of the expansion part 102 remain arched, as shown in FIG. 7(E). Thus, as for an interval between the bonded part 104 becomes shorter compared to a situation prior to air-filling, whereby the open/close valve 103 becomes loose, having wrinkles there. Since this causes crumples on the open/close valve 103, the air passage 103a may be left open at its crumpled portion, through which the air in the expansion part 102 leaks to the outside of the sealed body 101.
In view of the above-mentioned problem, the present invention provides an open/close valve which can avoid air leakage even when the expansion part is filled with air.